Numerous government and industry studies have shown that passenger car and truck operators are very negligent about maintaining proper inflation pressure in their tires. The effects of low tire pressure are threefold: First, the tire life is considerably reduced because of greatly increase tread wear due to high tire heat build-up. Second, tire rolling resistance is greatly increased resulting in higher gas consumption. Lastly, tire cornering and traction properties are severely degraded which in turn result in poor handling and braking performance of the vehicle. It is estimated by NHTSA that each year 670 lives are lost because of low tire pressure, and that the cost of accidents related to this amounts to $350 million. In addition, the fuel economy penalty of low tire pressure on cars and trucks is estimated at over $700 million annually.
Numerous devices have been developed to date to warn drivers of low tire pressure. Generally these devices fall into two categories: The first consists of some type of active pressure sensor which monitors tire pressure and gives a reading or warning on some type of visual electronic display mounted in the driver's compartment. Such devices are complex and very costly, and consequently have not found wide acceptance by users. The second type of device that has been developed is one which mounts in or replaces the normal inflation valve stem. These devices rely on a visual indication, such as a pop-up plunger, to indicate low tire pressure. While such devices are relatively inexpensive and simple they suffer from a number of problems. The most significant problem is that these devices violate the primary pressure seal at the tire inflation port. This raises a serious issue of reliability which is probably responsible for keeping all such devices off the market to date. Also, the operation, reliability and calibration of these devices are questionable when exposed to the mud, ice, snow, and salt involved in winter weather driving. Finally, it is highly unlikely that such devices would offer sufficient motivation to the driver to inflate his tires, especially in inclement weather. The Low Pressure Warning Device described herein circumvents all of these problems.